What mmss is talking bout is the theoretical ideal that there will be a 'cloud' that you connect to on the internet for everything you need. Your OS, files, applications, everythign will be in this Internet cloud that you can access from any terminal in the world. PC Mag hit on this last month pretty hard so a lot of it is still fresh in my mind. While the idea was good, it will probably never become reality for a number of reasons. Some of which Mak has hit on, others being things like if you purchase a software app and that company goes out of business. Well if you don't have a physical application and it is just in this 'cloud' then you SOL, opposed to now if they go out of business my application still works. Another is bandwidth use and the ungodly amount of bandwidth that would be used to run all of this information from your computer to the next. Another is infrastructure... I mean we can't even get a city wide Wi-Fi plan to work. They just ditched that plan about half a year ago after putting millions into this project. Chicago was supposed to be the first city, but they can't get Internet on a large scale to work. My point with that being on something as small as 'city wide Wi-Fi' we fall on our faces, much less the idea of using EVERYTHING via the Internet on your computer.
If this isn't what you were talking about, sorry for the long exlination, but I think it is related either way. Desktop OS's will be here for a long time, and will IF ANYTHING just get more complicated. You run into two issues here, obviously w/ more 'features' an OS becomes more vunerable to security threats (we are talking millions of lines of code here). At the same time the only way to really make a system secure is to isolate it or make it extremely simplistic - neither of which will happen.
Okay i'm off my soap box.